The standard procedure for making sourdough bread involves a long process. The basis for the process is fermentation of a wheat flour-based dough by bacterial organisms which have the ability to produce lactic and acetic acids. This fermentation process is maintained by daily additions of flour and other nutrient materials such as nonfat dry milk and occasionally potato flour. Portions of this "ferment" are then used by adding them to standard French bread or sourdough bread formulae. An example of a French sourdough bread formula is as follows:
______________________________________ French Bread Straight Dough Process Pounds ______________________________________ White Flour 100 Water 55-58 Salt 2 Sourdough ferment 20 ______________________________________
One of the difficulties attendant to the operation of this sourdough bread process is the need to maintain perfect fermentation conditions for the bacterial organisms and to make regular additions to the ferment every twenty-four hours.
The bacterial organisms commonly go through changes which frequently results in lowered production of acetic and lactic acids. The baker, therefore, is faced with considerable difficulty in maintaining a constant flavor level in sourdough breads produced in this fashion on a day-to-day basis.
The flavor of sourdough bread is based on its high acidity due to acetic and lactic acids. The total acidity of sourdough bread is roughly ten times that of conventional bread. Of this acidity, the acetic acid is the more important of the two acids in providing the characteristic sourdough flavor. Acetic acid is also the most volatile of the two acids. This volatility is probably responsible for the variation in the flavor of sourdough breads produced by the conventional process. The volatility of the acetic acid causes its escape from the sourdough bread ferment; this characteristic is also responsible for its evaporation during the oven baking step in making sourdough bread.
A convenient and safe and efficient sourdough bread compound which the baker would desire is a dry compound, one which can be handled with ease like flour. It is also one which can be packed in standardized packing materials and shipped long distances without loss of acetic and lactic acid. Such compounds of this type have not been available for commercial use.